We are interested in understanding signaling events in the thymus that regulate T cell development. Current efforts are aimed at delineating the role of evolutionarily conserved Wnt-beta-catenin-TCF pathway. To this end, we have manipulated the transcription factor TCF1 gene and the beta-catenin gene, which mediate the canonical Wnt signaling pathway. In this study we have used TCF1-deficient (TCF1-KO) mice, (beta-CAT) transgenic mice expressing transgenic beta-catenin as well as beta-CAT-KO) mice with beta-catenin deleted from T cells. Using these reagents we are studying the role of these transcription factore in the development of conventional as well as innate cells in the thymus.